/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.hadoop.hbase;

import java.io.Serializable;
import java.util.ArrayList;
import java.util.List;
import java.util.Locale;
import java.util.regex.Pattern;

import org.apache.hadoop.hbase.net.Address;
import org.apache.hadoop.hbase.util.Addressing;
import org.apache.hadoop.hbase.util.Bytes;
import org.apache.hbase.thirdparty.com.google.common.collect.Interner;
import org.apache.hbase.thirdparty.com.google.common.collect.Interners;
import org.apache.hbase.thirdparty.com.google.common.net.InetAddresses;
import org.apache.yetus.audience.InterfaceAudience;


/**
 * Name of a particular incarnation of an HBase Server.
 * A {@link ServerName} is used uniquely identifying a server instance in a cluster and is made
 * of the combination of hostname, port, and startcode.  The startcode distinguishes restarted
 * servers on same hostname and port (startcode is usually timestamp of server startup). The
 * {@link #toString()} format of ServerName is safe to use in the  filesystem and as znode name
 * up in ZooKeeper.  Its format is:
 * <code>&lt;hostname&gt; '{@link #SERVERNAME_SEPARATOR}' &lt;port&gt;
 * '{@link #SERVERNAME_SEPARATOR}' &lt;startcode&gt;</code>.
 * For example, if hostname is <code>www.example.org</code>, port is <code>1234</code>,
 * and the startcode for the regionserver is <code>1212121212</code>, then
 * the {@link #toString()} would be <code>www.example.org,1234,1212121212</code>.
 *
 * <p>You can obtain a versioned serialized form of this class by calling
 * {@link #getVersionedBytes()}.  To deserialize, call
 * {@link #parseVersionedServerName(byte[])}.
 *
 * <p>Use {@link #getAddress()} to obtain the Server hostname + port
 * (Endpoint/Socket Address).
 *
 * <p>Immutable.
 */
@InterfaceAudience.Public
public class ServerName implements Comparable<ServerName>, Serializable {
    private static final long serialVersionUID = 1367463982557264981L;

    /**
     * Version for this class.
     * Its a short rather than a byte so I can for sure distinguish between this
     * version of this class and the version previous to this which did not have
     * a version.
     */
    private static final short VERSION = 0;
    static final byte[] VERSION_BYTES = Bytes.toBytes(VERSION);

    /**
     * What to use if no startcode supplied.
     */
    public static final int NON_STARTCODE = -1;

    /**
     * This character is used as separator between server hostname, port and
     * startcode.
     */
    public static final String SERVERNAME_SEPARATOR = ",";

    public static final Pattern SERVERNAME_PATTERN = Pattern.compile(
            "[^" + SERVERNAME_SEPARATOR + "]+" + SERVERNAME_SEPARATOR + Addressing.VALID_PORT_REGEX + SERVERNAME_SEPARATOR + Addressing.VALID_PORT_REGEX + "$");

    /**
     * What to use if server name is unknown.
     */
    public static final String UNKNOWN_SERVERNAME = "#unknown#";

    private final String servername;
    private final long startcode;
    private transient Address address;

    /**
     * Cached versioned bytes of this ServerName instance.
     * @see #getVersionedBytes()
     */
    private byte[] bytes;
    public static final List<ServerName> EMPTY_SERVER_LIST = new ArrayList<>(0);

    /**
     * Intern ServerNames. The Set of ServerNames is mostly-fixed changing slowly as Servers
     * restart. Rather than create a new instance everytime, try and return existing instance
     * if there is one.
     */
    private static final Interner<ServerName> INTERN_POOL = Interners.newWeakInterner();

    protected ServerName(final String hostname, final int port, final long startcode) {
        this(Address.fromParts(hostname, port), startcode);
    }

    private ServerName(final Address address, final long startcode) {
        // Use HostAndPort to host port and hostname. Does validation and can do ipv6
        this.address = address;
        this.startcode = startcode;
        this.servername = getServerName(this.address.getHostname(), this.address.getPort(), startcode);
    }

    private ServerName(final String serverName) {
        this(parseHostname(serverName), parsePort(serverName), parseStartcode(serverName));
    }

    private ServerName(final String hostAndPort, final long startCode) {
        this(Address.fromString(hostAndPort), startCode);
    }

    /**
     * @param hostname
     * @return hostname minus the domain, if there is one (will do pass-through on ip addresses)
     * @deprecated Since 2.0. This is for internal use only.
     */
    @Deprecated
    // Make this private in hbase-3.0.
    static String getHostNameMinusDomain(final String hostname) {
        if(InetAddresses.isInetAddress(hostname))
            return hostname;
        String[] parts = hostname.split("\\.");
        if(parts == null || parts.length == 0)
            return hostname;
        return parts[0];
    }

    /**
     * @deprecated Since 2.0. Use {@link #valueOf(String)}
     */
    @Deprecated
    // This is unused. Get rid of it.
    public static String parseHostname(final String serverName) {
        if(serverName == null || serverName.length() <= 0) {
            throw new IllegalArgumentException("Passed hostname is null or empty");
        }
        if(!Character.isLetterOrDigit(serverName.charAt(0))) {
            throw new IllegalArgumentException("Bad passed hostname, serverName=" + serverName);
        }
        int index = serverName.indexOf(SERVERNAME_SEPARATOR);
        return serverName.substring(0, index);
    }

    /**
     * @deprecated Since 2.0. Use {@link #valueOf(String)}
     */
    @Deprecated
    // This is unused. Get rid of it.
    public static int parsePort(final String serverName) {
        String[] split = serverName.split(SERVERNAME_SEPARATOR);
        return Integer.parseInt(split[1]);
    }

    /**
     * @deprecated Since 2.0. Use {@link #valueOf(String)}
     */
    @Deprecated
    // This is unused. Get rid of it.
    public static long parseStartcode(final String serverName) {
        int index = serverName.lastIndexOf(SERVERNAME_SEPARATOR);
        return Long.parseLong(serverName.substring(index + 1));
    }

    /**
     * Retrieve an instance of ServerName.
     * Callers should use the equals method to compare returned instances, though we may return
     * a shared immutable object as an internal optimization.
     */
    public static ServerName valueOf(final String hostname, final int port, final long startcode) {
        return INTERN_POOL.intern(new ServerName(hostname, port, startcode));
    }

    /**
     * Retrieve an instance of ServerName.
     * Callers should use the equals method to compare returned instances, though we may return
     * a shared immutable object as an internal optimization.
     */
    public static ServerName valueOf(final String serverName) {
        return INTERN_POOL.intern(new ServerName(serverName));
    }

    /**
     * Retrieve an instance of ServerName.
     * Callers should use the equals method to compare returned instances, though we may return
     * a shared immutable object as an internal optimization.
     */
    public static ServerName valueOf(final String hostAndPort, final long startCode) {
        return INTERN_POOL.intern(new ServerName(hostAndPort, startCode));
    }

    @Override
    public String toString() {
        return getServerName();
    }

    /**
     * @return Return a SHORT version of {@link ServerName#toString()}, one that has the host only,
     * minus the domain, and the port only -- no start code; the String is for us internally mostly
     * tying threads to their server.  Not for external use.  It is lossy and will not work in
     * in compares, etc.
     */
    public String toShortString() {
        return Addressing.createHostAndPortStr(getHostNameMinusDomain(this.address.getHostname()), this.address.getPort());
    }

    /**
     * @return {@link #getServerName()} as bytes with a short-sized prefix with
     * the ServerName#VERSION of this class.
     */
    public synchronized byte[] getVersionedBytes() {
        if(this.bytes == null) {
            this.bytes = Bytes.add(VERSION_BYTES, Bytes.toBytes(getServerName()));
        }
        return this.bytes;
    }

    public String getServerName() {
        return servername;
    }

    public String getHostname() {
        return this.address.getHostname();
    }

    public String getHostnameLowerCase() {
        return this.address.getHostname().toLowerCase(Locale.ROOT);
    }

    public int getPort() {
        return this.address.getPort();
    }

    public long getStartcode() {
        return startcode;
    }

    /**
     * For internal use only.
     * @param hostName
     * @param port
     * @param startcode
     * @return Server name made of the concatenation of hostname, port and
     * startcode formatted as <code>&lt;hostname&gt; ',' &lt;port&gt; ',' &lt;startcode&gt;</code>
     * @deprecated Since 2.0. Use {@link ServerName#valueOf(String, int, long)} instead.
     */
    @Deprecated
    // TODO: Make this private in hbase-3.0.
    static String getServerName(String hostName, int port, long startcode) {
        final StringBuilder name = new StringBuilder(hostName.length() + 1 + 5 + 1 + 13);
        name.append(hostName.toLowerCase(Locale.ROOT));
        name.append(SERVERNAME_SEPARATOR);
        name.append(port);
        name.append(SERVERNAME_SEPARATOR);
        name.append(startcode);
        return name.toString();
    }

    /**
     * @param hostAndPort String in form of &lt;hostname&gt; ':' &lt;port&gt;
     * @param startcode
     * @return Server name made of the concatenation of hostname, port and
     * startcode formatted as <code>&lt;hostname&gt; ',' &lt;port&gt; ',' &lt;startcode&gt;</code>
     * @deprecated Since 2.0. Use {@link ServerName#valueOf(String, long)} instead.
     */
    @Deprecated
    public static String getServerName(final String hostAndPort, final long startcode) {
        int index = hostAndPort.indexOf(":");
        if(index <= 0)
            throw new IllegalArgumentException("Expected <hostname> ':' <port>");
        return getServerName(hostAndPort.substring(0, index), Integer.parseInt(hostAndPort.substring(index + 1)), startcode);
    }

    /**
     * @return Hostname and port formatted as described at
     * {@link Addressing#createHostAndPortStr(String, int)}
     * @deprecated Since 2.0. Use {@link #getAddress()} instead.
     */
    @Deprecated
    public String getHostAndPort() {
        return this.address.toString();
    }

    public Address getAddress() {
        return this.address;
    }

    /**
     * @param serverName ServerName in form specified by {@link #getServerName()}
     * @return The server start code parsed from <code>servername</code>
     * @deprecated Since 2.0. Use instance of ServerName to pull out start code.
     */
    @Deprecated
    public static long getServerStartcodeFromServerName(final String serverName) {
        int index = serverName.lastIndexOf(SERVERNAME_SEPARATOR);
        return Long.parseLong(serverName.substring(index + 1));
    }

    /**
     * Utility method to excise the start code from a server name
     * @param inServerName full server name
     * @return server name less its start code
     * @deprecated Since 2.0. Use {@link #getAddress()}
     */
    @Deprecated
    public static String getServerNameLessStartCode(String inServerName) {
        if(inServerName != null && inServerName.length() > 0) {
            int index = inServerName.lastIndexOf(SERVERNAME_SEPARATOR);
            if(index > 0) {
                return inServerName.substring(0, index);
            }
        }
        return inServerName;
    }

    @Override
    public int compareTo(ServerName other) {
        int compare;
        if(other == null) {
            return -1;
        }
        if(this.getHostname() == null) {
            if(other.getHostname() != null) {
                return 1;
            }
        } else {
            if(other.getHostname() == null) {
                return -1;
            }
            compare = this.getHostname().compareToIgnoreCase(other.getHostname());
            if(compare != 0) {
                return compare;
            }
        }
        compare = this.getPort() - other.getPort();
        if(compare != 0) {
            return compare;
        }
        return Long.compare(this.getStartcode(), other.getStartcode());
    }

    @Override
    public int hashCode() {
        return getServerName().hashCode();
    }

    @Override
    public boolean equals(Object o) {
        if(this == o)
            return true;
        if(o == null)
            return false;
        if(!(o instanceof ServerName))
            return false;
        return this.compareTo((ServerName) o) == 0;
    }

    /**
     * @param left
     * @param right
     * @return True if <code>other</code> has same hostname and port.
     */
    public static boolean isSameAddress(final ServerName left, final ServerName right) {
        // TODO: Make this left.getAddress().equals(right.getAddress())
        if(left == null)
            return false;
        if(right == null)
            return false;
        return left.getHostname().compareToIgnoreCase(right.getHostname()) == 0 && left.getPort() == right.getPort();
    }

    /**
     * Use this method instantiating a {@link ServerName} from bytes
     * gotten from a call to {@link #getVersionedBytes()}.  Will take care of the
     * case where bytes were written by an earlier version of hbase.
     * @param versionedBytes Pass bytes gotten from a call to {@link #getVersionedBytes()}
     * @return A ServerName instance.
     * @see #getVersionedBytes()
     */
    public static ServerName parseVersionedServerName(final byte[] versionedBytes) {
        // Version is a short.
        short version = Bytes.toShort(versionedBytes);
        if(version == VERSION) {
            int length = versionedBytes.length - Bytes.SIZEOF_SHORT;
            return valueOf(Bytes.toString(versionedBytes, Bytes.SIZEOF_SHORT, length));
        }
        // Presume the bytes were written with an old version of hbase and that the
        // bytes are actually a String of the form "'<hostname>' ':' '<port>'".
        return valueOf(Bytes.toString(versionedBytes), NON_STARTCODE);
    }

    /**
     * @param str Either an instance of {@link ServerName#toString()} or a
     * "'&lt;hostname&gt;' ':' '&lt;port&gt;'".
     * @return A ServerName instance.
     */
    public static ServerName parseServerName(final String str) {
        return SERVERNAME_PATTERN.matcher(str).matches() ? valueOf(str) : valueOf(str, NON_STARTCODE);
    }


    /**
     * @return true if the String follows the pattern of {@link ServerName#toString()}, false
     *  otherwise.
     */
    public static boolean isFullServerName(final String str) {
        if(str == null || str.isEmpty())
            return false;
        return SERVERNAME_PATTERN.matcher(str).matches();
    }
}
